From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 95396C33CB1 for ; Tue, 14 Jan 2020 10:31:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 70669207FF for ; Tue, 14 Jan 2020 10:31:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729485AbgANKbZ (ORCPT ); Tue, 14 Jan 2020 05:31:25 -0500 Received: from mx2.suse.de ([195.135.220.15]:41612 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725820AbgANKbY (ORCPT ); Tue, 14 Jan 2020 05:31:24 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id E3F33ACE0; Tue, 14 Jan 2020 10:31:20 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id CDB791E0D0E; Tue, 14 Jan 2020 11:31:19 +0100 (CET) Date: Tue, 14 Jan 2020 11:31:19 +0100 From: Jan Kara To: Kai Li Cc: jack@suse.cz, tytso@mit.edu, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, joseph.qi@linux.alibaba.com, gechangwei@live.cn, wang.yongd@h3c.com, wang.xibo@h3c.com Subject: Re: [PATCH] jbd2: clear JBD2_ABORT flag before journal_reset to update log tail info when load journal Message-ID: <20200114103119.GE6466@quack2.suse.cz> References: <20200111022542.5008-1-li.kai4@h3c.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200111022542.5008-1-li.kai4@h3c.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Thanks for the patch! Just some small comments below: On Sat 11-01-20 10:25:42, Kai Li wrote: > Fixes: 85e0c4e89c1b "jbd2: if the journal is aborted then don't allow update of the log tail" This tag should come at the bottom of the changelog (close to your Signed-off-by). > If journal is dirty when mount, it will be replayed but jbd2 sb > log tail cannot be updated to mark a new start because > journal->j_flags has already been set with JBD2_ABORT first > in journal_init_common. > When a new transaction is committed, it will be recorded in block 1 > first(journal->j_tail is set to 1 in journal_reset). If emergency > restart again before journal super block is updated unfortunately, > the new recorded trans will not be replayed in the next mount. > It is danerous which may lead to metadata corruption for file system. I'd slightly rephrase the text here so that it is more easily readable and correct some grammar mistakes. Something like: If the journal is dirty when the filesystem is mounted, jbd2 will replay the journal but the journal superblock will not be updated by journal_reset() because JBD2_ABORT flag is still set (it was set in journal_init_common()). This is problematic because when a new transaction is then committed, it will be recorded in block 1 (journal->j_tail was set to 1 in journal_reset()). If unclean shutdown happens again before the journal superblock is updated, the new recorded transaction will not be replayed during the next mount (because of stale sb->s_start and sb->s_sequence values) which can lead to filesystem corruption. Otherwise the patch looks good to me so feel free to add: Reviewed-by: Jan Kara (again this is added to the bottom of the changelog like the 'Fixes' tag or 'Signed-off-by' tag). Honza > > Signed-off-by: Kai Li > --- > fs/jbd2/journal.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c > index 5e408ee24a1a..069b22eba795 100644 > --- a/fs/jbd2/journal.c > +++ b/fs/jbd2/journal.c > @@ -1710,6 +1710,11 @@ int jbd2_journal_load(journal_t *journal) > journal->j_devname); > return -EFSCORRUPTED; > } > + /* > + * clear JBD2_ABORT flag initialized in journal_init_common > + * here to update log tail information with the newest seq. > + */ > + journal->j_flags &= ~JBD2_ABORT; > > /* OK, we've finished with the dynamic journal bits: > * reinitialise the dynamic contents of the superblock in memory > @@ -1717,7 +1722,6 @@ int jbd2_journal_load(journal_t *journal) > if (journal_reset(journal)) > goto recovery_error; > > - journal->j_flags &= ~JBD2_ABORT; > journal->j_flags |= JBD2_LOADED; > return 0; > > -- > 2.24.0.windows.2 > -- Jan Kara SUSE Labs, CR